/* roulang page: index */
:root {
            --primary: #2563EB;
            --primary-dark: #1D4ED8;
            --accent-cyan: #0EA5E9;
            --accent-purple: #7C3AED;
            --accent-green: #10B981;
            --bg-main: #F8FAFC;
            --bg-dark: #0B0F19;
            --text-heading: #0F172A;
            --text-body: #334155;
            --text-muted: #64748B;
            --card-border: rgba(226, 232, 240, 0.8);
            --card-shadow: 0 4px 20px -2px rgba(15, 23, 42, 0.05);
            --card-shadow-hover: 0 12px 30px -4px rgba(37, 99, 235, 0.12);
        }

        body {
            font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
            letter-spacing: 0.02em;
            line-height: 1.8;
            color: var(--text-body);
            background-color: var(--bg-main);
            overflow-x: hidden;
        }

        h1, h2, h3, h4, h5, h6 {
            line-height: 1.3;
            color: var(--text-heading);
            font-weight: 700;
        }

        .custom-card {
            background: #FFFFFF;
            border: 1px solid var(--card-border);
            border-radius: 16px;
            box-shadow: var(--card-shadow);
            transition: transform 0.28s ease, box-shadow 0.28s ease, border-color 0.28s ease;
        }
        .custom-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--card-shadow-hover);
            border-color: rgba(37, 99, 235, 0.3);
        }

        .dark-card {
            background: rgba(255, 255, 255, 0.03);
            border: 1px solid rgba(255, 255, 255, 0.08);
            border-radius: 16px;
            transition: all 0.28s ease;
        }
        .dark-card:hover {
            background: rgba(255, 255, 255, 0.06);
            border-color: rgba(56, 189, 248, 0.4);
            transform: translateY(-4px);
        }

        /* 手风琴平滑展开 */
        details summary::-webkit-details-marker {
            display: none;
        }
        details[open] summary .arrow-icon {
            transform: rotate(180deg);
        }